1. Field of the Invention
The present invention is directed generally to a ventilation conduit damper assembly for use primarily with a turbine ventilator. More specifically, the present invention is directed to such a ventilation damper assembly provided with automatic, temperature responsive, actuating means whereby the amount of movement of the damper vanes, over a preselected temperature range, is controlled.
2. Description of the Prior Art
Dampers for use in air conduits or ducts are generally well known and are utilized, for example, in connection with stoves, fireplaces, furnaces and the like. Typically a damper assembly will consist of a moveable vane or vanes which are positionable to control the amount of air flow through the conduit within which the damper is placed. In many applications the damper is either normally open or normally closed, with position selection and control being accomplished manually. Dampers are additionally often used in conjunction with the ventilating systems in private homes and other buildings where it is desired to provide a measure of ventilation control.
In some areas of the country where rather hot weather is experienced during at least a portion of the year, it is often desirable to provide a means for ventilating an otherwise confined portion of a building, for example, the attic in a private home, in order to minimize the buildup therein of excessive heat and/or humidity. This ventilation is often provided by the use of a turbine air ventilator of a known type in which wind causes the turbine blades to rotate, producing in effect a pumping action, assisting the air flow out of the area provided with the ventilating conduit.
While turbine ventilation systems are quite effective in promoting air flow, they have, in the past, suffered from the lack of an effective automatic means to control the amount of air removed. Obviously the air flow should be at a maximum during hot weather when the temperature in the area to be ventilated is high, but just as obviously the ventilation should be much less when the temperature in the area to be ventilated is lower. Unnecessary ventilation in periods of cool temperatures may contribute to excessive loss of heat and a consequent increase in heating costs. While this problem of present ventilation systems is recognized, the attempted solutions have been less than satisfactory.
Although some type of adjustable damper is desirable, in a number of instances no such adjustable flow control means has been provided. When a damper is provided, it often is of the type where the position of the damper means is adjustable by, for example, a manual movement of the vanes. Since the space to be ventilated, typically an attic, is often inaccessible, the homeowner is not apt to manually adjust the damper as often as he should to provide for efficient ventilation in hot periods or for retention of heated air during cold periods. Other adjusting means such as chain pulls, elongated adjusting rods and the like have been provided, but again either these are difficult to use or else the homeowner simply forgets to change the damper position. Hence the damper is open when it should be closed or closed when it should be open so that it is ineffectual in performing its intended function. With the increasing cost of power used for heating and air-conditioning, it becomes readily apparent why an automatic damper system should be utilized in conjunction with ventilation systems.
Unfortunately, the few prior automatic adjustable dampers which have been contemplated or manufactured have been unable to perform their desired function in an effective, economical manner. These automatic controls, when available, have suffered from high cost, undependability, a failure to provide simple means to vary the range of temperature over which the damper is controlled, and a propensity to become damaged or disabled in cases of temperature fluctations beyond the range for which they were designed. This lack of dependability, high cost and incidence of damage to the device by abnormal temperature fluctations has combined to limit the use and acceptance of automatic damper control systems in home ventilating systems and the like.